ZyXEL VMG4825 User Guide - Page 147

IEEE 802.1Q Tag

Page 147 highlights

Chapter 10 Quality of Service (QoS) Table 51 Policer Setup: Add/Edit LABEL Meter Type DESCRIPTION This shows the traffic metering algorithm used in this policer. The Simple Token Bucket algorithm uses tokens in a bucket to control when traffic can be transmitted. Each token represents one byte. The algorithm allows bursts of up to b bytes which is also the bucket size. The Single Rate Three Color Marker (srTCM) is based on the token bucket filter and identifies packets by comparing them to the Committed Information Rate (CIR), the Committed Burst Size (CBS) and the Excess Burst Size (EBS). Committed Rate Committed Burst Size The Two Rate Three Color Marker (trTCM) is based on the token bucket filter and identifies packets by comparing them to the Committed Information Rate (CIR) and the Peak Information Rate (PIR). Specify the committed rate. When the incoming traffic rate of the member QoS classes is less than the committed rate, the device applies the conforming action to the traffic. Specify the committed burst size for packet bursts. This must be equal to or less than the peak burst size (two rate three color) or excess burst size (single rate three color) if it is also configured. Conforming Action This is the maximum size of the (first) token bucket in a traffic metering algorithm. Specify what the VMG does for packets within the committed rate and burst size (greenmarked packets). NonConforming Action Available Class • Pass: Send the packets without modification. • DSCP Mark: Change the DSCP mark value of the packets. Enter the DSCP mark value to use. Specify what the VMG does for packets that exceed the excess burst size or peak rate and burst size (red-marked packets). • Drop: Discard the packets. • DSCP Mark: Change the DSCP mark value of the packets. Enter the DSCP mark value to use. The packets may be dropped if there is congestion on the network. Select a QoS classifier to apply this QoS policer to traffic that matches the QoS classifier. Selected Class Highlight a QoS classifier in the Available Class box and use the > button to move it to the Selected Class box. OK Cancel To remove a QoS classifier from the Selected Class box, select it and use the < button. Click OK to save your changes. Click Cancel to exit this screen without saving. 10.8 Technical Reference The following section contains additional technical information about the VMG features described in this chapter. IEEE 802.1Q Tag The IEEE 802.1Q standard defines an explicit VLAN tag in the MAC header to identify the VLAN membership of a frame across bridges. A VLAN tag includes the 12-bit VLAN ID and 3-bit user priority. The VLAN ID associates a frame with a specific VLAN and provides the information that devices need to process the frame across the network. VMG4825-B10A User's Guide 147

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Chapter 10 Quality of Service (QoS)
VMG4825-B10A User’s Guide
147
10.8
Technical Reference
The following section contains additional technical information about the VMG features described in
this chapter.
IEEE 802.1Q Tag
The IEEE 802.1Q standard defines an explicit VLAN tag in the MAC header to identify the VLAN
membership of a frame across bridges. A VLAN tag includes the 12-bit VLAN ID and 3-bit user
priority. The VLAN ID associates a frame with a specific VLAN and provides the information that
devices need to process the frame across the network.
Meter Type
This shows the traffic metering algorithm used in this policer.
The
Simple Token Bucket
algorithm uses tokens in a bucket to control when traffic can be
transmitted. Each token represents one byte. The algorithm allows bursts of up to
b
bytes
which is also the bucket size.
The
Single Rate Three Color Marker
(srTCM) is based on the token bucket filter and
identifies packets by comparing them to the Committed Information Rate (CIR), the
Committed Burst Size (CBS) and the Excess Burst Size (EBS).
The
Two Rate Three Color Marker
(trTCM) is based on the token bucket filter and
identifies packets by comparing them to the Committed Information Rate (CIR) and the
Peak Information Rate (PIR).
Committed
Rate
Specify the committed rate. When the incoming traffic rate of the member QoS classes is
less than the committed rate, the device applies the conforming action to the traffic.
Committed
Burst Size
Specify the committed burst size for packet bursts. This must be equal to or less than the
peak burst size (two rate three color) or excess burst size (single rate three color) if it is also
configured.
This is the maximum size of the (first) token bucket in a traffic metering algorithm.
Conforming
Action
Specify what the VMG does for packets within the committed rate and burst size (green-
marked packets).
Pass:
Send the packets without modification.
DSCP Mark:
Change the DSCP mark value of the packets. Enter the DSCP mark value to
use.
Non-
Conforming
Action
Specify what the VMG does for packets that exceed the excess burst size or peak rate and
burst size (red-marked packets).
Drop:
Discard the packets.
DSCP Mark:
Change the DSCP mark value of the packets. Enter the DSCP mark value to
use. The packets may be dropped if there is congestion on the network.
Available Class
Selected Class
Select a QoS classifier to apply this QoS policer to traffic that matches the QoS classifier.
Highlight a QoS classifier in the
Available Class
box and use the
>
button to move it to the
Selected Class
box.
To remove a QoS classifier from the
Selected Class
box, select it and use the
<
button.
OK
Click
OK
to save your changes.
Cancel
Click
Cancel
to exit this screen without saving.
Table 51
Policer Setup: Add/Edit
LABEL
DESCRIPTION